The present invention relates to a position information input method and device and, more particularly, to a position information input method and device for inputting position information which indicates a coordinate position on the display screen of an information processing apparatus such as a computer.
Conventionally, as a position information input device (pointing device) for inputting position information for moving a cursor on the display screen of an information processing apparatus such as a computer, a device such as a trackball has been proposed and used. To make the operation space unnecessary, a trackball is constituted by a spherical body, e.g., a ball which is rotatable and so supported as to expose a part of its outer circumferential portion to the outside, and a circuit for converting the rotation amount of this spherical body into an electrical signal. The amount obtained by rotating the exposed portion of the spherical body when operated with a finger of an operator is converted into an electrical signal. In response to this signal, position information is input to a control unit of an information processing apparatus such as a computer.
A conventional position input device with this arrangement, therefore, has the following problems.
1. When the spherical body is to be rotated with a finger, a finger of an operator becomes fatigued since the spherical body must be rotated with a force larger than its rotational friction.
2. The moving speed of a cursor on a screen is limited by the rotational friction of the spherical body even if the cursor is to be moved on the screen at high speed.
3. The spherical body requires cleaning because it is in direct contact with a finger in operation.
4. When the operability of the device is taken into consideration, the size of the spherical body is limited; i.e., the miniaturization of the spherical body has its limit.